Method of precipitating metal ions with 8-sulfonamidoquinolines



United States Fatent Office 3,337,555 Patented Aug. 22, 1967 3,337,555 METHOD OF PRECIPITATING METAL IONS WITH S-SULFONAMIDOQUINOLINES John H. Billman, Bloomington, Ind., and Robert Chernin,

Yonkers, N.Y., assignors to Indiana University Foundation, Bloomington, Ind.

No Drawing. Original application Feb. 26, 1963, Ser. No. 261,200, now Patent No. 3,268,538, dated Aug. 23, 1966. Divided and this application May 16, 1966, Ser. No. 560,356

1 Claim. (Cl. 260-270) This application is a division of our co-pending application, Ser. No. 261,200, filed Feb. 26, 1963.

This invention relates to a novel group of selective chelating agents. More particularly, this invention relates to a novel group of metal-ion chelating agents based upon the quinoline nucleus.

It has been well recognized for many years that 8-hydroxyquinoline is one of the most useful of all chelating agents since it forms unsoluble precipitates with a wide variety of metal ions. More recently, 8-mercaptoquinoline has been shown to have a similar ability to complex a wide variety of metal ions. Although both of these reagents are extremely useful in the quantitative determination of individual ions, they are of little use in determining the amount of one metal ion in admixture with other metal ions. In other words, both 8-hydroxyquinoline and 8-mercaptoquinoline are quite non-specific or non-selective in their ability to discriminate among ions.

It is an object of this invention to provide a novel quinoline-type chelating agent which is quite selective in its action. It is a further object of this invention to provide novel qualitative as Well as quantitative analytical procedures based upon the ability of our novel chelating agents to discriminate among metal ions in solution. Other objects of this invention will become apparent from the description which follows:

In fulfillment of the above and other objects, this invention first provides a novel group of quinoline chelating agents represented by the following formula:

wherein R is a member of the group consisting of C C alkyl, C -C alkenyl and m is a number from 2; R is C -C alkyl, C -C alkyl oxy, nitro, halo, and

and Z is oxygen, sulfur, sulfonyl or sulfoxide.

In the above formulas, the term C C alkyl includes group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, n-amyl, isoamyl, 2-pentyl, 3- pentyl, 3-methyl-m-butyl, 2-methyl-2-butyl, and the like. Similarly, the term C -C alkenyl includes groups such as vinyl, alkyl, methallyl, crotyl, 3-methyl-l-pentenyl-l, 3 methyl 2 pentenyl -1, 2 methyl 3 pentenyl-l and the like. Among the halogens which R can represent are included fluorine, chlorine, bromine, iodine and astatine.

Also included within the scope of this invention are compounds represented by the above formula but in 5 which the quinoline nucleus is substituted by alkyl, alkenyl, alkoxy, nitro, halo or the like groups, as well as compounds in which a quinoxaline, quinazoline, cinnoline, indole, 1,5-naphthpyridine, 1,6-naphthpyridine, 2H- 1,4 benzoxazine, 4H-3,1 benzoxazine, 1,2 benziosoxazole, 1,2-benzisothiozole, pyrido (2,3-b) pyrazine, benzoxazole, benzthiazole, 2,1 benzisoxazole or the like ring system has replaced the quinoline nucleus, the sole requirement for the latter compounds being that the amino groups and one ring nitrogen have the same relative geometry as in 8-aminoquinoline.

The compounds of this invention are prepared by reacting an 8-aminoquinoline with an appropriately substituted sulfonylchloride in the presence of an inert dispersing agent. A basic substance is customarily present to combine with the hydrogen chloride which is produced in the reaction. We prefer to employ pyridine as the dis- I persing agent since it is also most suitable for reaction with the hydrogen chloride inasmuch as it is a stronger base than S-aminoquinoline itself and frees any molecules of that substance which might be tied up by hydrogen chloride (in the form of an acid addition salt) for further reaction.

Illustrative compounds coming with the scope of the above formula include the following: 8-(p-toluenesulfonamido) quinoline 8-(p-anisidenesulfonamido) quinoline 8-(o-chlorophenylslulfonamido) quinoline 8-(3,4-dimethoxyphenylsulfonamido) quinoline 8-(m-nitrophenylsulfonamido) quinoline 8- (p-bromophenylsulfonamido) quinoline 3,3-bis(quinoline-8-sulfamoyl) biphenyl sulfone 3,3'-bis(quinoline-8-sulfamoyl) biphenyl oxide 4,4'-bis(quinoline-S-sulfamoyl) biphenyl sulfide 40 2,2'-bis(quinoline-S-sulfamoyl) biphenyl sulfoxide S-(methylsulfonamido) quinoline 8-(n-amylsulfonamido) quinoline 8-methallylsulfonamido) quinoline 8-(2,4-difluorophenylsulfonamido) quinoline The compounds of this invenion are useful in precipitating one or more of a group of six metal ions from solution. The metal ions which are precipitated from aqueous solutions thereof by means of an 8-sulfonamidoquinoline of this invention include silver, mercuric, cupric, plumbous, cobaltous and Zinc. The precipitate which is formed between one of the above metal ions and an 8-sulfonamidoquinoline of this invention is in the form of a chelate. When the 8-sulfonamidoquinoline is a bidentate compound, these novel chelates can be represented by the following formula:

I \lll/ wherein M is a metal of the group consisting of Ct Co, Pb Zn Hg and Ag, 11 is the valence of the metal ion; R is C -C alkyl, C C alkenyl and R is halo, nitro, C C alkyl or C C alkyloxy. When M represents a bivalent metal ion, there are, of necessity, two molecules of the 8-sulfonamidoquinoline for each metal ion. When M represents the monovalent metal ion, silver, however, there are also two molecules of S-sulfonamidoquinoline present for each silver ion in the chelate. In this silver chelate, the second molecule of the 8- sulfonamido quinoline is presumably bound to the silver ion by two coordinate linkages.

In the quadridentate bis(quinoline-8-sulfamoyl) biphenyl sulfoxide type of chelating agent there is, of course, only one molecule of the chelating agent per metal ion. These quadridentate chelates can be represented by the following formula:

I N I wherein M and Z have the same meaning as hereinabove. As before, when M is silver, the metal is bound by one ionic bond and three coordinate bonds whereas when M is one of the above bivalent metal ions, it is held by two of each type of bond.

The precipitation of copper, cobalt, lead, zinc, mercury or silver ions from solutions by means of an 8-sulfonamidoquinoline represented by the above formula can be employed for purifying metals from their ores, for the quantitative determination of the same metals as ions and other similar uses. In addition, the precipitated chelates are colored and thus their formation can be used as a qualitative indication of the presence of the chelated ion. Each of the above 8-sulfonamidoquinolines gives a characteristic color with each of the above ions. The following table lists the color of the chelate for four chelating agents with each of the above 6 ions.

TABLE .-OOLOR OF CHELATES 41- pared by substituting the appropriate sulfonyl halide for p-tolyl chloride in the above example.

8 (2,5 dimethylbenzenesulfonamido) quinoline; M.P.=148-9 C., Anal., Calc., N, 8.98; S, 10.26. Found: N, 9.00; S, 10.27.

S-(methylsulfonamido) quinoline; M.P.=l43-4 C. Anal., Calc., N, 14.61; S, 14.40. Found: N, 12.85; S, 14.32.

3.3 bis(quinoline 8 sulfamoyl) biphenyl sulfone; M.P.=2034 C. Anal., Calc., N, 8.89; S, 15.24. Found: N, 8.98; S, 1.5.26.

EXAMPLE 2 Precipitation of cations A reagent solution was prepared by dissolving 0.1 mole of 8-(p-toluenesulfonamido) quinoline in one liter of 95% ethanol. (Acetone can also be used here.) One milliliter of this solution was mixed with 2 ml. of a pH 5.2 acetic acid-sodium acetate bufier and 1 ml. of a 0.1 molar cupric nitrate solution. The mixture was heated at about 80 C. in a water bath for 15 min. and was then cooled. The resulting brown precipitate consisting of the cupric chelate of 8-(p-toluenesulfonarnido) quinoline was separated by filtration, and was dried. The chelate contained two molecules of S-(p-toluenesulfonamido) quinoline for each cupric ion.

Other buifer solutions, as for example, a pH 8.4 am monium hydroxide-ammonium acetate butter can be used in place of the acetic acid-sodium acetate buffer in the above example.

The above procedure can be employed for separating Cu, Co+ Pb, Hg, Zn, and Ag+ ions singly or together from solutions containing additional ions including one or more of the following: Li, Na, K the amrnonium ion, Tl, Rb, Cs, Hg, Be, Mg, Ca, So, Su, Fe, Ni, Cd, Ba, Mn, Pa+ Au, Co, Ru, In, Ga, V+ Ti, Sn, Zo, Th, Pt+ and Sb+ We claim:

The method of quantitatively precipitating an ion of the group consisting of Co, Cu+ Pb+ Hg+ Zn+ and Ag'*' which comprises heating a mixture comprising 1 Other of the 8-(sulfonamido) quinolines of this invention give comparable colors with the above six ions.

This invention is further illustrated by the following specific examples.

EXAMPLE 1 Preparation of 8-(sulf0namid0) quinolines A solution of 4.3 g. (0.03 mole) of 8-aminoquinoline in ml. of pyridine is placed in a 100 ml. flask equipped with stirring means and cooler in an ice water bath. Five and seven tenths grams (0.03 mole) of p-tolyl chlorides is added with stirring to the solution in small portions over a two hour period. The reaction mixture is then poured with vigorous stirring into 200 ml. of cold water. A pink solid precipitates and is separated by filtration. The filter cake is thoroughly washed with cold water. Recrystallization of the filter cake from 95 percent ethanol yields a white crystalline solid melting at about 153-4 C. Anal, Calc., N, 9.41; S, 1072. Found: N, 9.43; S, 10.59.

The following 8-(sulfonamido) quinolines were prepart by volume of a 0.1 molar aqueous solution of said ion, 1 part by volume of a reagent solution containing 0.1 moles of an 8-(sulfonamido) quinonoli-ne represented by the formula:

\N/ l'm S O2 it wherein R is a member of the group consisting of C C alkyl, C C alkenyl and wherein m is a number from 0-2, and R is a member of 5 6 the group consisting of C -C alkyl, C -C alkyloxy, halo, References Cited and UNITED STATES PATENTS 3,153,514 12/1964 Seaborg 250-270 2 5 3,268,538 8/1966 Billman et a1. 260-288 wherein Z is a member of the group consisting of O, S, OTHER REFERENCES S0 and SQ in one liter of a sOlvent selected from the Bozhevolnov et a1.: Chem. Abstr., vol. 54, col. 2067621, group 'COHSIStIIIg of 95% ethanol and acetone, and 2 parts (1960) by volume of a pH 5.2 acetic acid-sodium acetate buffer 10 solution at about 80 C. in a water bath for about 15 minutes, cooling said mixture, separating the resulting ALEX MAZELPrlmW-y Emmmer v metahchelate of said compound by filtration drying and DONALD D AUS A ism, Emmi-"en weighing said precipitate, sald precipitate having 2 mole- 15 cules of said compound per metal ion. 

